Selector marking system



Feb, 17, 1953 H. l.. LEslGNE 2,629,019

SELECTOR MARKING SYSTEM Filed April 28, 1949 Patented Feb. 17, 1953 SELECTOR. MAR-KING SYSTEM Henri Louis Lesigne, Vanves, France, assignor to Compagnie Industrielle des Telephones, Paris,

France Application April 28, 1949, Serial N o. 90,164 In France April 28, 1948 1 claim. l

This invention relates to the selection of the out lines in an automatic-switching exchange.

In the switching networks comprising several exchanges, these are connected together by bundles of lines whose installation is expensive and of which the highest possible efficiency should be obtained. The efiiciency increases at the same time as the number of the lines of .the bundle if these lines, the number oi which is determined by the number of the calls to be transmitted, constitute a single perfect group, that is, a group wholly available to each of the selecting units; if the bundle consists of several line groups the highest possible eiiiciency is no longer reached.

A single perfect group would be formed if all the out lines oi a bundle were connected to the banks of all the out selectors, but the capacity oi these devices would then be increased beyond measure. It has also been proposed to modify the control circuits s0 as to allow the selections to proceed only towards selectors capable of linding a free line in the partial bundles to which they give access.

It is also known to resort to partial bundles with grading multiples but a busy signal is then sent without ground since it only relates to a ,partial bundle on which the hunting has taken place. Indeed a continuous hunting has been proposed should the relevant line group be found busy but the operations are then delayed until a line has become free in .the partial bundle, which entails an important waste of time and a substantial wea-r of the devices. In no case is a single perfect group achieved.

This necessitates to increase the number of the out lines to such an extent that the probability for an out selector to 'nd busy all the lines of the partial line bundle .to which it gives access should be sufliciently low.

This invention allows of constituting out lines in a single Iperfect group and to thus obtain the highest efficiency from the bundles. It is applicable where .the selection takes place by means of rst group selectors and second group selectors, a first plurality of which gives access to some directions and a second plurality of which gives access to other directions, and where a single marking wire is multipled on registers at one of its extremities and on selectors at its other g extremity so as to permit the orientation of the selectors from the registers. Such a system has been described for instance in my U. S. Patent 2,529,166 and in the British Patent 668,261, which corresponds to my U. S. application Ser. No.

617,379 referred to in the second paragraph of this U. S. patent and is entirely concerned with this system. In these patents the circuits in the registers and in the selectors have been described at full length. They may remain unaltered in the system of the present invention.

In the system according to the present invention, which will now be described with reference to the drawing, the lines which constitute a bundle for at least one direction are distributed over both pluralities of second group selectors but nevertheless remain all simultaneously accessible through the medium of the marking wire; the latter provides at all times for the orientation of the selectors exclusively towards the devices connected to free lines.

The accompanying figure, Which represents by way of example an embodiment of the invention, shows the line of a calling subscriber I having access to three line bundles I0, I3, I5 corresponding to different directions by means of a circuit of connection 3 comprising a line under 2 and a iirst group selector 4 which itself gives access to two second group selectors I and 8 whose connecting relays are shown at 2'I and 23 respectively. The register 6, connected through the nder 5 to the circuit of connection, orients the selectors by means of the control wire 22 for the direction I5, the control wire 23 for the direction i3 and the control wire 24 for the direction I0. The equipments of the line bundles I0 and I5 are shown at 9 and lll respectively; it is furthermore assumed that the bundle I3 is divided into two line groups, whose equipment II and I2 are connected to fthe selectors 'l and 8 respectively. For the purpose of simplicity the line groups themselves will be designated by references I I and I2 in the following. .The word equipment is here intended to mean the assembly of the terminals (line, control and test) of the diierent second group selectors on which each line is multipled.

As conventional in the art, each of the lines of the line bundle I0 which lead to the same direction is multipled to a contact of a plurality of selectors I similar to the single selector 1 diagrammatically shown so that any of these lines is accessible over any one of these selectors 'I. Each of the lines of the line bundle I5 which lead to another direction is similarly multipled to a contact of a plurality of selectors 8. As conventional in the `art the wiper of each of selectors 'I and 8 is similarly multipled to a contact of a plurality of first .group selectors 4 similar to the single first group selector II which has been represented, so that any selector 'I or 8 is accessible over any one of the selectors 4 to one contact of which it is multipled. Finally, as appears from the foregoing and from the drawing, some of the lines of the line bundle I3 which lead to a further direction are multipled to a contact of the selectors 'I and others to a contact of the selectors 8. Each of the marking wires 22, 23 and 24 bears two arrows, one of which is directed towards the register 6 and indicates, as is conventional in the art, that the wire is multipled to several registers and the other of which is directed towards the selectors and indicates that the wire, at its other extremity, is multipled t0 the above mentioned several selectors.

Two busy relays I 6 and I'I control the line groups I2 and II respectively. Relays I6 and Il operate when all lines of groups I2 and II respectively are busy. A suitable conventional arrangement consists in mounting a relay on each trunk and in connecting in series one contact of all relays so. as toclose a circuit when all trunks are simultaneously busy. Such an arrangement is for example described in Telephony by Atkinson, London 1948, page 239, under the heading Group Engaged Tone and illustrated in Fig.

358 on page 240.

Relays IB and I7 open at I8 and I9 .the control wire 23 so as to render inaccessible, if desired, the selectors 8 and 1; the unidirectional-conductivity members 20 and 2| prevent the formation of common points in the control wires.

The operation is las follows:

When the subscriber calls for direction IB, the register 6 orients a selector 4 through the wire 24 on a selector 1, then it orients the latter selector through the wire 24 on one line of the bundle I0; again, for 4direction I5, a selector 4 is oriented through the wire 22 on a selector 8, and the latter is itself oriented on a line of .the

bundle I5; the selector 4 is oriented through -L the wire 23 and may stop on any one of selectors 'I and `8 if both line groups II and I2 0i bundle I3 have lines free, because the wire 23 is connected either .by the contact I8 and the element 20. or lby the contact I9 and the elementZI,

The register then orients the selector 'I or the selector 8 on any of the lines of groups I0 and II or I5 and I2 respectively; if all the lines of group II are busy, relay I'I opens I9 and the l selector 4 can no longer be connected with the selectors 1, whereas lthe selectors 8 remain accessible to it, owing to the contact I8 held closed. The Contact I9 has no influence on the wires 22 and 24; it prohibits the acces-s to the selectors 'i only for the communications towards the bundle I3; these devices however remain accessible for the calls towards the bundle I0.

V The advantageous results of the invention reside in the fact that a selector such as 4 can provide for the transmission of the communication designed for a bundle such as I3 in the same conditions as if it had on its bank of contact studs all the lines of the bundle I3 in a single perfect group. The risk thus disappears of seeing the selection take a way ywithout any irnmediate outlet, while the -communication is possible through another way.

The applications of this invention may be extended to all systems in which it may be advantageous to avoid the overcharge of the devices through communication overloads: the automatic control is here achieved by the control yon the line bundles.

I claim:

Telecommunication switching system for trunking the outgoing communications from a telecommunication exchange comprising rst group selectors, a first plurality of second group selectors, a second plurality of second group selectors, a rst and a second plurality of outgoing lines each o1" which is multipled to a position of each selector of said first plurality of second group selectors, a third and a fourth plurality of outgoing lines each of which is multipled to a position of each selector of said second plurality of second group selectors, a marking wire dividing into a rst ybranch multipled on those positions of said `first group selectors which give access to said :First plurality of said second group selectors, a second branch multipled on those positions of said rst group selectors which give access to said second plurality of said second group selec-tors, a third branch multipled to those positions of said iirst plurality of said second group selectors .to which the lines of said second plurality of outgoing lines are multipled and a fourth branch multipled to those positions of said second plurali-ty of said second group selectors to which the lines of said fourth plurality of outgoing lines are multipled, means for cutting off said first branch when a predetermined number of lines of said second plurality of lines are busy, means for cutting oi said second branch when a predetermined number of lines of said four-th plurality of lines are busy, and a unidirectional cell on each of said rst and second branches.

HENRI LOUIS LESIGNE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,559,736 Bellamy Nov. 3, 1925 1,900,969 Wright Mar. 14, 1933 2,030,412 yStearn Feb. 11, 1936 2,137,422 Taylor Nov. 22, 1938 2,138,594 Brofos Nov. 29, 1938 2,217,084 Von Konig Oct. 8, 1940 2,421,919 Avery June 10, 1947 2,431,313 Den Hertog Nov. 25, 1947 

